Method for predicting carbon sink in reforestation of mangrove forest in culture pond

Abstract

The invention discloses a cultivation pond mangrove forest reforestation carbon sink prediction method, relates to the technical field of carbon sink evaluation, and aims to solve the problem that related carbon sinks cannot be accurately predicted in the prior art. The method comprises the following steps: respectively measuring carbon dioxide and methane emissions of the mangrove forest and the coastal culture pond and performing conversion calculation to obtain carbon emission decrement; measuring mangrove forest plant carbon sink and soil carbon burial rate to obtain carbon sink increment; and measuring organic carbon reserves of different soils, and calculating the change of the reserves. And finally, integrating the three aspects of data, performing conversion by recovering the mangrove seedlings for 20 years, and calculating the reforestation carbon sink of the mangrove forest in the culture pond. According to the method, the difference of carbon emission and soil carbon sink neglected in the prior art is comprehensively considered, and an effective way is provided for accurately evaluating the reforestation carbon sink of the mangrove forest in the culture pond through an innovative calculation mode.

Description

Technical Field

[0001] The present invention relates to the technical field of carbon sink assessment, and particularly to a method for predicting the carbon sink of mangrove reforestation in aquaculture ponds. Background Art

[0002] Mangroves are an important part of coastal wetlands and have the ability to efficiently absorb carbon dioxide from the atmosphere and sequester carbon in the soil for a long time. This enables them to play an important role in the global ecosystem's response to climate change. Therefore, they are included in the 2013 Wetland Greenhouse Gas Supplement List of the Intergovernmental Panel on Climate Change (IPCC) and are also incorporated into the ecosystems of the voluntary carbon contributions of countries in the United Nations, highlighting their important value in global ecology and climate regulation.

[0003] In the 20th century, a large number of mangroves in China's coastal areas were reclaimed into aquaculture ponds, which became one of the important reasons for the degradation of mangroves in China. The Chinese government has realized the role of mangroves in responding to climate change, maintaining biodiversity, and coastal protection, and has started to vigorously promote the restoration of mangroves. The mangrove reforestation in aquaculture ponds is taken as one of the main measures for mangrove restoration because the carbon sink generated by the mangrove reforestation in aquaculture ponds is of great significance for increasing the carbon sink in coastal wetlands and helps to enhance the ecological functions of coastal wetlands and the ability to respond to climate change.

[0004] There are differences in carbon emissions between aquaculture ponds and mangroves. Moreover, after mangroves are reclaimed into aquaculture ponds, the bait added to the aquaculture ponds will affect the content of organic carbon at the bottom of the ponds. However, the existing methods for predicting the carbon sink of mangrove reforestation in aquaculture ponds have defects. For example, they only consider the part of carbon sequestration and increase in carbon sink by mangrove plants after the aquaculture ponds are restored into mangroves; although Dey et al. predicted the vegetation and soil carbon storage in the mangrove restoration area in 2024, they did not conduct a comparative analysis of the vegetation and soil carbon sinks brought about by the mangrove reforestation in aquaculture ponds. At the same time, they also ignored the differences in carbon emissions between aquaculture ponds and mangroves, as well as the differences in carbon sinks between the bottom of aquaculture ponds and mangrove soils. These deficiencies lead to the inability of existing methods to comprehensively and accurately predict the carbon sink situation of mangrove reforestation in aquaculture ponds and are difficult to meet the needs of precise assessment of the carbon sink in mangrove ecosystems. Summary of the Invention

[0005] In view of the deficiencies in the prior art, the present invention provides a method for predicting the carbon sink of mangrove reforestation in aquaculture ponds. This method comprehensively calculates the carbon sink contribution of mangrove reforestation in aquaculture ponds by considering various factors such as the difference in carbon sinks between the bottom of aquaculture ponds and mangrove soils, the contribution of plant carbon sequestration and soil carbon sink after mangrove reforestation, and the difference in carbon emissions between aquaculture ponds and mangroves. This method makes up for the loopholes in the prior art and provides a more comprehensive and scientific prediction approach.

[0006] To achieve the above object, the present invention provides the following technical solutions:

[0007] A prediction method for the carbon sink of mangrove reforestation in aquaculture ponds, comprising the steps of:

[0008] Obtain the carbon dioxide and methane emissions of mangroves and coastal aquaculture ponds, convert the carbon dioxide and methane emissions into the respective carbon emissions of mangroves and coastal aquaculture ponds, and subtract the respective carbon emissions to obtain the reduction in carbon emissions after the aquaculture pond is restored to a mangrove;

[0009] Obtain the mangrove plant carbon sink and the soil carbon burial rate, and obtain the increase in the carbon sink after the coastal aquaculture pond is restored to a mangrove according to the sum of the mangrove plant carbon sink and the soil carbon burial rate;

[0010] Obtain the organic carbon reserves of the bottom soil after the mangrove is reclaimed into a coastal aquaculture pond and the mangrove soil at the same depth, and obtain the change in the organic carbon reserves of the bottom soil caused by the reclamation of the mangrove into a coastal aquaculture pond according to the difference in the organic carbon reserves of the bottom soil and the mangrove soil at the same depth;

[0011] Calculate the carbon sink of mangrove reforestation in aquaculture ponds based on the reduction in carbon emissions after the coastal aquaculture pond is restored to a mangrove, the increase in the carbon sink after the coastal aquaculture pond is restored to a mangrove, and the change in the organic carbon reserves of the bottom soil caused by the reclamation of the mangrove into a coastal aquaculture pond.

[0012] For the prediction method of the carbon sink of mangrove reforestation in aquaculture ponds as described above, further,

[0013] Convert the carbon dioxide and methane emissions into the respective carbon emissions of mangroves and coastal aquaculture ponds, specifically:

[0014]

[0015] Subtract the respective carbon emissions to obtain the reduction in carbon emissions after the aquaculture pond is restored to a mangrove, specifically:

[0016] E C = E CA - E CM ;

[0017] In the formula, E CM and E CA are the carbon emissions of mangroves and aquaculture ponds respectively, and are the carbon dioxide emissions of mangroves and aquaculture ponds respectively, and are the methane emissions of mangroves and aquaculture ponds respectively, and E C is the reduction in carbon emissions after the aquaculture pond is restored to a mangrove.

[0018] The prediction method of the carbon sink of mangrove reforestation in the aquaculture pond as described above. Further,

[0019] The carbon sink C of mangrove plants P includes the litter carbon sink C L and the carbon sink C of tree growth G , where

[0020] The litter carbon sink C L is:

[0021]

[0022] The carbon sink C of tree growth G is:

[0023]

[0024] Adding the litter carbon sink C L and the carbon sink C of tree growth G , that is, C P = C L + C G , to obtain the carbon sink C of mangrove plants P ;

[0025] The soil carbon burial rate C S , specifically:

[0026] C S = BD × C t % × SR;

[0027] The sum of the carbon sink of mangrove plants and the soil carbon burial rate gives the increment C M of the carbon sink after the coastal aquaculture pond is restored to mangroves, specifically:

[0028] C M = C P + C S ;

[0029] In the formula, B i is the biomass of the litter collected in the i-th month, C Bi % is the carbon content of the litter collected in the i-th month, A w is the area of the litter collection net, f(D, H) is the allometric equation for calculating tree biomass, D i1 and D i2 are the diameters at breast height of the i-th tree in the quadrat at the beginning and end of the measurement year respectively, H i1 and H i2 are the tree heights of the i-th tree in the quadrat at the beginning and end of the measurement year respectively, C i1 % and C i2% are the carbon contents of the i-th tree in the quadrat at the beginning and end of one year respectively, n is the number of trees in the quadrat, A p is the area of the quadrat, BD is the bulk density of the soil core sample, C t % is the carbon content of the soil core sample, SR is the sedimentation rate of the soil; C P is the plant carbon sink, C L is the litter carbon sink, C G is the carbon sink for tree growth, C S is the soil carbon burial rate, C M is the increment of the carbon sink after the aquaculture pond is restored to mangrove forest.

[0030] For the prediction method of the carbon sink of the aquaculture pond mangrove reforestation as described above, further,

[0031] According to the difference in the organic carbon storage of the bottom soil and the mangrove soil at the same depth, the change in the organic carbon storage of the bottom soil caused by the reclamation of mangroves into coastal aquaculture ponds is obtained, specifically:

[0032] SOC C = SOC M - SOC A ;

[0033] In the formula, SOC C is the change in the organic carbon storage of the bottom soil caused by the reclamation of mangroves into aquaculture ponds, SOC A is the organic carbon storage of the bottom soil after reclamation into a coastal aquaculture pond, SOC M is the organic carbon storage of the mangrove soil at the same depth.

[0034] For the prediction method of the carbon sink of the aquaculture pond mangrove reforestation as described above, further,

[0035] According to the reduction of carbon emissions, the increment of the carbon sink after the coastal aquaculture pond is restored to mangrove forest, and the change in the organic carbon storage of the bottom soil caused by the reclamation of mangroves into coastal aquaculture ponds, the carbon sink of the aquaculture pond mangrove reforestation is calculated:

[0036] C T = 20×(E C + C M ) + SOC C ;

[0037] In the formula, C T is the carbon sink of the aquaculture pond mangrove reforestation, and the reduction of emissions and the increment of the carbon sink are converted according to the total carbon emissions and the total carbon sink of the mangrove seedlings restored to forest in 20 years.

[0038] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0039] (1) When predicting the carbon sink of mangrove reforestation in aquaculture ponds, the existing technologies have obvious limitations. It does not take into account the reduced carbon emissions during the process of restoring aquaculture ponds into mangroves. The aquaculture pond and the mangrove ecosystem are different, and their carbon emission levels also vary. After the aquaculture pond is transformed into a mangrove, the carbon emissions will decrease accordingly, and this reduction is crucial for accurately assessing the carbon sink. At the same time, the existing technologies also do not pay attention to the differences in carbon sinks between the bottom of the aquaculture pond and the mangrove soil. Due to the different soil properties and organic carbon contents of the aquaculture pond and the mangrove, their carbon sequestration capacities are also different, but the existing technologies do not include this difference in the scope of carbon sink prediction. The prediction method proposed by the present invention measures the carbon dioxide and methane emissions of mangroves and coastal aquaculture ponds respectively, and obtains the carbon emission difference through conversion calculation, that is, the reduction of carbon emissions after the aquaculture pond is restored into a mangrove; at the same time, it measures the mangrove plant carbon sink, the soil carbon burial rate and the organic carbon reserves of different soils and calculates the difference, fully considering various factors, making the prediction result more accurate.

[0040] (2) Traditional prediction methods often only focus on one or a few aspects. For example, they only consider the carbon sequestration and increment part of mangrove plants after the aquaculture pond is restored into a mangrove. This single consideration method cannot comprehensively reflect the true situation of the carbon sink. The prediction method proposed by the present invention points out that the carbon sink of mangrove reforestation in aquaculture ponds consists of three parts: the reduction of carbon emissions, the increment of afforestation carbon sink, and the increment of soil carbon sink. The reduction of carbon emissions reflects the positive impact of the change in carbon emissions during the ecosystem transformation on the carbon sink; the increment of afforestation carbon sink covers the carbon fixed by mangrove plants through litter and their own growth during the growth process; the increment of soil carbon sink takes into account the contribution of mangrove soil to carbon storage. This multi-dimensional carbon sink composition framework comprehensively and systematically presents the carbon sink situation of mangrove reforestation in aquaculture ponds, providing a new and more scientific method for carbon sink prediction. BRIEF DESCRIPTION OF THE DRAWINGS

[0041] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following will briefly introduce the drawings required to be used in the embodiments. Obviously, the drawings described below are only some embodiments of the present application. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0042] Figure 1 It is a schematic flowchart of the prediction method for the carbon sink of mangrove reforestation in aquaculture ponds in the embodiments of the present invention. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0043] Next, in combination with the accompanying drawings in the embodiments of the present invention, the technical solutions in the embodiments of the present invention will be clearly and completely described. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without making creative efforts belong to the scope of protection of the present application.

[0044] Embodiment:

[0045] It should be noted that the terms "include" and "have" in the embodiments of the present invention and any variations thereof are intended to cover non-exclusive inclusion. For example, a process, method, system, product, or device that includes a series of steps or units does not necessarily limit to those steps or units clearly listed, but may include other steps or units not clearly listed or inherent to these processes, methods, products, or devices.

[0046] Figure 1 is a schematic flow chart of the prediction method for the carbon sink of mangrove reforestation in aquaculture ponds in the embodiments of the present invention. As Figure 1 shown, a prediction method for the carbon sink of mangrove reforestation in aquaculture ponds provided by the embodiments of the present invention may specifically include the following steps:

[0047] Step 1: Obtain the carbon dioxide and methane emissions of mangroves and coastal aquaculture ponds, convert the carbon dioxide and methane emissions into the respective carbon emissions of mangroves and coastal aquaculture ponds, and subtract the respective carbon emissions to obtain the reduction in carbon emissions after the coastal aquaculture pond is restored to mangroves.

[0048] In this step, the carbon dioxide and methane emissions of mangroves and coastal aquaculture ponds are measured respectively. This is because there are differences in the ecological system functions of mangroves and coastal aquaculture ponds, and the amounts of carbon dioxide and methane they emit into the atmosphere are also different.

[0049] Then, since both carbon dioxide and methane are greenhouse gases, to uniformly measure the carbon emission situation, it is necessary to convert the measured carbon dioxide and methane emissions into carbon emissions. This conversion is based on the ratio of the molecular weight of carbon dioxide and methane to the number of carbon atoms and is calculated by the following formula. For example, for mangroves, the carbon emission E CM The calculation formula is Among them, is the carbon dioxide emission of mangroves, is the methane emission of mangroves, and are the conversion coefficients for converting carbon dioxide and methane into carbon emissions (obtained based on the ratio of the molecular weight of carbon dioxide and methane to the number of carbon atoms); similarly, the carbon emission E of the coastal aquaculture pond can be obtainedCA Calculation formula Such a conversion can compare the carbon emissions of mangroves and coastal aquaculture ponds under the same carbon measurement standard.

[0050] Next, after obtaining the respective carbon emissions of mangroves and coastal aquaculture ponds, subtract the two, that is, E C = E CA - E CM , and the obtained difference E C is the reduction in carbon emissions after the coastal aquaculture pond is restored to a mangrove. This reduction reflects the effect of restoring the aquaculture pond to a mangrove in reducing carbon emissions. If this reduction is positive, it indicates that after the aquaculture pond is restored to a mangrove, the carbon emissions have indeed decreased, which provides a quantitative basis for evaluating the role of mangrove reforestation in addressing climate change and reducing greenhouse gas emissions.

[0051] Step 2: Obtain the carbon sink of mangrove plants and the soil carbon burial rate, and obtain the increase in the carbon sink after the coastal aquaculture pond is restored to a mangrove according to the sum of the carbon sink of mangrove plants and the soil carbon burial rate.

[0052] In this step, the carbon sink of mangrove plants consists of two parts: the litter carbon sink and the carbon sink of tree growth. The litter carbon sink comes from the litter such as fallen leaves, fruits, and flowers of mangroves. During measurement, these litter are collected through litter nets monthly within a year, and then their total dry weight and carbon content are measured. Through the formula Calculated, where B i is the biomass of the litter collected in the i-th month, C Bi % is the carbon content of the litter collected in the i-th month, and A w is the area of the litter collection net.

[0053] Then, the carbon sink of tree growth is related to the growth of trees. By measuring the tree diameter at breast height and tree height within a year, the change in the growth of trees within a year is predicted using the allometric growth equation, and combined with the tree carbon content to obtain.

[0054] Among them, the calculation formula for the carbon sink of tree growth is where f(D, H) is the allometric growth equation for calculating the tree biomass, D i1 and D i2 are the tree diameters at breast height of the i-th tree in the quadrat at the beginning and end of the measurement year respectively, H i1 and H i2 are the tree heights of the i-th tree in the quadrat at the beginning and end of the measurement year respectively, C i1 % and C i2 % are the carbon contents of the i-th tree in the quadrat at the beginning and end of the measurement year respectively, and n is the number of trees in the quadrat, Ap is the area of the quadrat.

[0055] Next, add the litter carbon sink C L and the carbon sink C G of tree growth, i.e., C P = C L + C G to obtain the mangrove plant carbon sink C P .

[0056] The soil carbon burial rate reflects the soil's ability to store carbon. During measurement, by obtaining soil core samples, analyzing their bulk density BD, carbon content C t %, and the sedimentation rate SR of the soil, and using the formula C S = BD × C t % × SR, calculate the soil carbon burial rate C S .

[0057] Then, add the mangrove plant carbon sink C P and the soil carbon burial rate C S , i.e., C M = C P + C S ; the obtained C M is the increment of the carbon sink after the aquaculture pond is restored to mangroves. This carbon sink increment data is of great significance for evaluating the positive contribution of aquaculture pond mangrove reforestation to the carbon sink. It is an indicator for measuring the enhancement degree of the carbon sink function of the mangrove ecosystem and can provide strong data support for the benefit evaluation of relevant ecological projects and the research on the carbon cycle of the ecosystem.

[0058] Step 3: Obtain the organic carbon storage of the bottom soil of the mangrove reclaimed into a coastal aquaculture pond and the mangrove soil at the same depth, and obtain the change in the organic carbon storage of the bottom soil caused by the mangrove reclaimed into a coastal aquaculture pond according to the difference between the organic carbon storage of the bottom soil and the mangrove soil at the same depth;

[0059] In this step, for the bottom soil of the mangrove reclaimed into a coastal aquaculture pond, the method of taking core samples at the bottom of the aquaculture pond is adopted. The obtained core samples are stratified, and then the organic carbon content and bulk density of each layer of soil are measured respectively. Combining with the thickness of each layer, calculate the organic carbon storage SOC A of the bottom soil of the coastal aquaculture pond through corresponding calculations. This method of stratified measurement and calculation can more accurately reflect the actual storage situation of the organic carbon in the bottom soil of the aquaculture pond because the organic carbon content and properties of the soil at different depths may vary.

[0060] Then, for mangrove soils at the same depth, a measurement method similar to that for the bottom soils of aquaculture ponds was adopted, i.e., taking columnar samples, layering, measuring the organic carbon content and bulk density, and then calculating in combination with the thickness to obtain the soil organic carbon stock SOC of mangrove soils at the same depth. M By measuring the two soils at the same depth, the scientificity and accuracy of subsequent comparisons were ensured, and interference factors caused by differences in soil depth in the change of soil organic carbon stock could be effectively excluded.

[0061] Next, subtract the soil organic carbon stock SOC of the bottom soil after the mangrove at the same depth is reclaimed into a coastal aquaculture pond M from the soil organic carbon stock SOC of the mangrove at the same depth A , i.e., SOC C = SOC M - SOC A ; the obtained difference SOC C is the change in the soil organic carbon stock of the bottom soil caused by the reclamation of the mangrove into an aquaculture pond. This change value reflects the increase or decrease in the soil organic carbon stock during the reclamation process. If SOC C is positive, it indicates that the soil organic carbon stock of the bottom soil decreases after the mangrove is reclaimed into an aquaculture pond; if it is negative, it means that the organic carbon stock increases. This data is very important for accurately evaluating the change trend of soil carbon sink during the reforestation of mangroves in aquaculture ponds, and is one of the important parameters for calculating the carbon sink of mangrove reforestation in aquaculture ponds, which can provide a basis for in-depth study of the carbon cycle and carbon sink function of the mangrove ecosystem.

[0062] Step 4: Calculate the carbon sink of mangrove reforestation in aquaculture ponds based on the reduction in carbon emissions after the coastal aquaculture pond is restored to mangroves, the increase in carbon sink after the coastal aquaculture pond is restored to mangroves, and the change in the soil organic carbon stock of the bottom soil caused by the reclamation of the mangrove into a coastal aquaculture pond.

[0063] Integrating the reduction in carbon emissions after the coastal aquaculture pond is restored to mangroves, the increase in carbon sink after the coastal aquaculture pond is restored to mangroves (the above reduction in emissions and increase in carbon sink are converted according to the total carbon emissions and total carbon sink of the red mangrove seedlings restored to forest in 20 years) and the change in the soil organic carbon stock of the bottom soil caused by the reclamation of the mangrove into a coastal aquaculture pond, the calculation formula is C T = 20×(E C + C M ) + SOC C ; where C T is the carbon sink of mangrove reforestation in aquaculture ponds.

[0064] In the description of this specification, the description referring to terms such as "one embodiment", "some embodiments", "example", "specific example", or "some examples" means that the specific features, structures, materials, or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials, or characteristics described can be combined in a suitable manner in any one or more embodiments or examples. In addition, without contradiction, those skilled in the art can combine and combine the different embodiments or examples described in this specification and the features of different embodiments or examples.

[0065] The above embodiments are only for illustrating the technical concept and features of the present invention, and the purpose is to enable those ordinary skilled in the art to understand the content of the present invention and implement it accordingly, and cannot be used to limit the protection scope of the present invention. Any equivalent changes or modifications made according to the essence of the content of the present invention should be covered within the protection scope of the present invention.

Claims

1. A prediction method for the carbon sink of mangrove reforestation in aquaculture ponds, characterized in that, Including the steps: Obtain the carbon dioxide and methane emissions of mangroves and coastal aquaculture ponds, convert the carbon dioxide and methane emissions into the respective carbon emissions of mangroves and coastal aquaculture ponds, and subtract the respective carbon emissions to obtain the reduction in carbon emissions after the aquaculture ponds are restored to mangroves; Obtain the mangrove plant carbon sink and soil carbon burial rate, and obtain the increase in the carbon sink after the coastal aquaculture ponds are restored to mangroves based on the sum of the mangrove plant carbon sink and soil carbon burial rate; Obtain the organic carbon reserves of the bottom soil after the mangroves are reclaimed into coastal aquaculture ponds and the mangrove soil at the same depth, and obtain the change in the organic carbon reserves of the bottom soil caused by the reclamation of mangroves into coastal aquaculture ponds based on the difference between the organic carbon reserves of the bottom soil and the mangrove soil at the same depth; Calculate the carbon sink of mangrove reforestation in aquaculture ponds based on the reduction in carbon emissions after the coastal aquaculture ponds are restored to mangroves, the increase in the carbon sink after the coastal aquaculture ponds are restored to mangroves, and the change in the organic carbon reserves of the bottom soil caused by the reclamation of mangroves into coastal aquaculture ponds.

2. The prediction method of the carbon sink of mangrove reforestation in aquaculture ponds according to claim 1, wherein: Converting the carbon dioxide and methane emissions into the respective carbon emissions of mangroves and coastal aquaculture ponds specifically is: Subtracting the respective carbon emissions to obtain the reduction in carbon emissions after the aquaculture ponds are restored to mangroves specifically is: E C = E CA - E CM ; where, E CM and E CA are the carbon emission amounts of the mangrove forest and the aquaculture pond respectively, and are the carbon dioxide emission amounts of the mangrove forest and the aquaculture pond respectively, and are the methane emission amounts of the mangrove forest and the aquaculture pond respectively, and E C is the reduction in carbon emission after the aquaculture pond is restored to a mangrove forest.

3. The prediction method of the carbon sink of mangrove reforestation in aquaculture ponds according to claim 1, wherein: Mangrove plant carbon sink C P including litter carbon sink C L and carbon sink C for tree growth G , where Litter carbon sink C L is as follows: Carbon sink C for tree growth G is as follows: Add the litter carbon sink C L and the carbon sink C G for tree growth, i.e., C P = C L + C G to obtain the mangrove plant carbon sink C P ; Soil carbon burial rate C S , specifically: C S = BD × C t % × SR; The sum of the carbon sink of mangrove plants and the soil carbon burial rate yields the increment C of the carbon sink after the coastal aquaculture ponds are restored to mangroves M , specifically: C M = C P + C S ; where B i is the biomass of the litter collected in the i-th month, C Bi % is the carbon content of the litter collected in the i-th month, A w is the area of the litter collection net, f(D, H) is the allometric equation for calculating tree biomass, D i1 and D i2 are the diameters at breast height of the i-th tree in the quadrat measured at the beginning and end of the year, respectively, H i1 and H i2 are the tree heights of the i-th tree in the quadrat measured at the beginning and end of the year, respectively, C i1 % and C i2 % are the carbon contents of the i-th tree in the quadrat measured at the beginning and end of the year, respectively, n is the number of trees in the quadrat, A p is the area of the quadrat, BD is the bulk density of the soil core sample, C t % is the carbon content of the soil core sample, SR is the sedimentation rate of the soil; C P is the plant carbon sink, C L is the litter carbon sink, C G is the carbon sink for tree growth, C S is the soil carbon burial rate, C M is the increment of the carbon sink after the aquaculture pond is restored to mangroves.

4. The prediction method of the carbon sink of mangrove reforestation in aquaculture ponds according to claim 1, wherein: Obtaining the change in the organic carbon reserves of the bottom soil caused by the reclamation of mangroves into coastal aquaculture ponds based on the difference between the organic carbon reserves of the bottom soil and the mangrove soil at the same depth specifically is: SOC C = SOC M - SOC A ; where SOC C is the change in the bottom soil organic carbon storage caused by the reclamation of mangroves into aquaculture ponds, SOC A is the bottom soil organic carbon storage after reclamation into coastal aquaculture ponds, and SOC M is the organic carbon storage of mangrove soil at the same depth.

5. The prediction method of the carbon sink of mangrove reforestation in aquaculture ponds according to claim 1, wherein: Calculating the carbon sink of mangrove reforestation in aquaculture ponds based on the reduction in carbon emissions after the coastal aquaculture ponds are restored to mangroves, the increase in the carbon sink after the coastal aquaculture ponds are restored to mangroves, and the change in the organic carbon reserves of the bottom soil caused by the reclamation of mangroves into coastal aquaculture ponds: C T = 20×(E C + C M ) + SOC C ; Where C T is the carbon sink of mangrove reforestation in the aquaculture pond. The reduction of emissions and the increase of carbon sink are based on the total carbon emissions converted from the restoration of mangrove seedlings to mature forests in 20 years and the total carbon sink of mangroves.

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